Transmission gear for motor vehicles



Oct. 5, 1965 o. SCHWAB 3,209,618

TRANSMISSION GEAR FOR MOTOR VEHICLES Original Filed April 23, 1959 2Sheets-Sheet 1 Fig. I

112 III 109 1 100 1 H4 101 M E 10 115 Fig. 3

Jn venfor:

Oct. 5, 1965 o. SCHWAB TRANSMISSION GEAR FOR MO'IOR VEHICLES 2Sheets-Sheet 2 Original Filed April 23, 1959 w 6 \LM 4 4 4 6 L/ 4 6 6 6I] n United States Patent 11 Claims. Zci. 74-688) This invention relatesto vehicle transmissions and more particularly to vehicle transmissionsof the torque converter type as disclosed in prior'copending applicationSN. 808,397, now abandoned, filed April 23, 1959, with respect to whichthe present application is a division.

It is an object of the invention to provide a transmission which can beshifted automatically with smoothness of operation and without loss oftractive power.

It is another object of the invention to provide a transmission whichwill be simple to construct and economical to manufacture.

It is a further object of the invention to provide a transmission havingshifting reaction torque elements for planetary gear sets and one-wayengaging devices through which sufiicient torque transmission engagementis effected at the time of greatest positive torque conversion of thetorque converter.

It is a still further object of the invention to provide a torqueconversion transmission having an adjustable speed by means of anarrangement of gears and means for adjusting the r.p.m. of the drivingshaft relative the driven shaft in shifting.

An additional object of the invention is to provide an arrangementwhereby, if desired, additional gear shift mechanism may be attached soas to increase the number of speeds possible with the basic mechanism.

A still further object of the invention is to provide for increasedtorque transmission for reverse speed.

All of the objects are attained in one or more of the embodiments of theinvention as hereinbelow described.

Briefly, my invention comprises an automatic type of transmissionwherein shifting is effected by means of oil or air pressure or anyother'suitable means. The general arrangement comprises a hydro-dynamictorque converter as a first stage coupled with a change speed planetarygear mechanism having constantly meshing gears. A particular feature ofthe arrangement resides in the utilization of reaction torque elementsand oneway engaging devices for changing speeds via respective gearpairs. The converter is used as a single-circuit rotor; that is to say,the torsional input is positively geared as long as the speed of theturbine wheel is less than that of the impeller. However, when theturbine wheel reaches the speed of the impeller, torque conversionceases. Under such conditions the converter operates as a fluid clutch.In time of starting, friction drive clutch means is utilized to effecttorque transmission owing to a large slip in the converter at this time.Such friction drive clutch means, when used, during starting needsconsiderably more transmission surface than is required after the partsof the converter have come up to the same speed. The present inventionhas the unique feature that each stage of the change-speed gear inforward speed is equipped with two reaction torque elements, one suchelement being fixedly connected with the respective shaft while theother is connected to the shaft through the intermediary of a one-wayengaging means. The

first-mentioned element is used for shifting, while the vehicle isstanding still or during subsequent speed change. The other element(110), however, is engaged only while the vehicle is standing still andis disengaged only after completed travel. The one-way means, in effecta freewheeling device, takes over the function of engaging anddisengaging its torque element at individual stages of travel.

Another feature of the invention resides in the use of a hollow shaft toform the driving element of the changegear mechanism in all stages oftransmission, including reverse gear. This minimizes stress on the gearteeth.

The invention will now be described in detail in conjunction with theappended drawing in which all figures are schematic and diagrammatic,FIGS. 1 through 4 showing only one-half of the arrangement in each case,it being understood that the half, not shown, is identical with thatwhich is shown, as follows:

FIG. 1 shows a torque converter transmission with a two-speed planetarygear coupled in series therewith in which the converter is used inconjunction with a clutch in direct drive;

FIG. 2 is similar to FIG. 1 but shows a three-speed planetary gear;

FIG. 3 shows a three-speed planetary gear arrangement as in FIG. 2, butwithout any clutch bridging the converter, direct drive thus beingthrough the converter only;

FIG. 4 shows a converter and change-speed gear orrangement having sixforward speeds.

Referring now to FIG. 1, a drive shaft 101 is shown for the input whileoutput is take off a driven shaft 102. A clutch 113 is provided betweenthe driving and driven shaft; when the clutch is disengaged, shaft 101drives impeller 106 of torque converter 103. So long as there is adifference in speeds between the impeller 106-and the turbine wheel 107of the torque converter, and so long as the torsional input therefor isgeared positively, the reaction vane wheel 104 is maintained stationaryby means of the one-way device 105 attached to the transmission housing.Turbine 107 is carried on a hollow shaft 108, which shaft is rotativelymounted on the driven shaft 102, and is integral with a drum 112 to theinterior of which is fastened ring gears 145 and 146 of two planetarygear systems. Thus, the ring gears are driven by turbine 107. Inconjunction with ring gear 145 is a sun gear 147 carried on a hollowshaft 124 to which it is fixed. Similarly, ring gear 146 is associatedwith a sun gear 148 likewise carried on and fixed to hollow shaft 124.Hollow shaft 124 is rotatively mounted on driven shaft 102 and connectsthe two sun gears with frictional brakes 109 and 110. A friction disk114 is provided for the releasable two-way brake 109, which disk isfixed to the hollow shaft 124, while releasable one-way brake hasfriction disk 115 carried by means of a one-way engaging device 127which is secured to the shaft 124. Between ring gear and sun gear 147planet pinions 149 are arranged on a spider 151 fixedly secured to thedriven shaft 102. In a similar manner, planet pinions 150 are carried bya spider 116 intermediate the ring gear 146 and sun gear 148. The spider116 also serves as a support for the brake disk for a brake 111, forreverse speed.

At the outset of torque transmission, the frictional brakes 109 and 110are engaged, whereas clutch 113 remains disengaged. Accordingly, drivenshaft 102 is operated by converter 103, hollow shaft 108, ring gear 145,and spider 151. This chain of transmission is effected because shaft 124and thus sun gears 147 and 143 are restrained from rotation, the one-waydevice 127 being in locking position because of the starting resistance.Thus, both brakes 109 and 110 participate in power transmission at theoutset. Upon sufficient acceleration of the vehicle, brake 109 may beopened and clutch 113 closed, thus coupling driven shaft 102 directlywith drive shaft 101. -At this time hollow shaft 124, via spider 151,

commences to rotate and one-way device 127 releases brake disk 115 dueto increase in speed. In shifting 'back, that is, upon opening clutch113 and closing brake 109, shaft 101. At this time hollow shaft 124, viaspider 151, transmission which rotates at an accelerated pace when thevehicle is traveling on a level stretch, so that shifting takes placesmoothly and without any delay. During this operation, the one-waydevice 127 remains disengaged.

If, however, the vehicle meets resistance, such as in going up a grade,then one-way device 127 reacts against shaft 124 to bring into play bothbrakes 109 and 110 for effecting increased torque to the driven shaft102.

For reverse speed, the brake 111 is provided, having a friction disk 116integral with the spider of the second planetary gear arrangement 146,148 and 150.

Referring now to FIG. 2, the arrangement is similar to that shown inFIG. 1 except that the planetary gear is provided with two forwardspeeds. In order to effect this, a second hollow shaft 258 is carried onthe first sun gear shaft 224 which shaft 258 carries an additional sungear 253 meshed with a planetary gear 252. The planetary gear 252 isfixedly connected so that it rotates integrally with planetary gear 250of the second set of planetary gears. Hollow shaft 258 can be sloweddown by means of brakes 254 and 255. Brake 254 is fixedly connected witha hollow shaft 258 via a friction disk 256 while a friction disk 257,part of brake 255, reacts via the one-way device 259 against hollowshaft 258. Thus, it is possible to start with first or second gear.Otherwise, the mode of operation is the same as that shown in thearrangement of FIG. 1.

Referring to FIG. 3, an arrangement somewhat similar to FIG. 2 is shownexcept that transmission in all speeds, including direct transmission,is effected by means of the torque converter 303. Accordingly, no clutchparalleling the torque converter has been provided. Instead, a clutch371 is provided which has a driving disk 372 fixedly connected to thedriven shaft 302. Driving disk 372 is disposed within a drum 312 whichcarries the ring gears 345 and 346. The mode of operation is the same asthat heretofore set forth in connection with FIG. 2.

FIG. 4 shows an arrangement generally similar to FIG. 3 wherein atransmission stage in the form of a planetary gear is utilized,connected to a change speed gear for the purpose of doubling the numberof speeds.

In order to effect smooth, uninterrupted, tractive force duringshifting, a pair of friction brakes 466 and 468 are provided disposedwithin a drum 461 of an auxiliary transmission stage. In order to engagethe latter stage, a brake 468 is provided having a driving disk 469fixedly carried on the hollow shaft 470, which brake 468 is engaged,thus connecting driving disk 469 with the transmission housing via shaft470, a sun gear 463 disposed on driven shaft 402 driving a planetarygear 462 which revolves within the drum 461 and drives a driven shaft465 by means of the spider 464. Each time brake 468 is disengaged andbrake 466 engaged, the driving disk of the latter effects rotation ofthe transmission as a block due to the fact that such driving disk isfixed on the driven shaft 402.

A one-Way brake 475 is shown as disposed between hollow shaft 470 andthe hub 474 of the hollow drum 461, which brake 475 prevents the drum461 from rotating in the direction of the reaction torque effected dueto disengagement of clutch 468.

The two brakes 466 and 468, when operated simultaneously, can also serveas brakes for the vehicle. In such case, the brakes are oil immersed toeffect heat dissipation.

This form of the invention differs from FIG. 3 which uses a clutch fordirect speed disposed on the driven shaft in the sense that a clutch 471is provided within a hollow drum 412 on driving shaft 424, which islikewise hollow. The arrangement has the advantage of effecting smallstress on the gear teeth. A clutch 413, paralleling limited to theprecise illustration herein given, except as set forth in the appendedclaims.

What is claimed is:

1. A variable speed transmission for vehicles comprising an input shaft,an output shaft, at least two planetary gear units each having an inputelement, an output element, and at least one reaction element, drivemeans operatively connected to the input shaft and directly connected tothe input elements of said planetary gear units for simultaneousrotation thereof, a control shaft directly interconnecting the reactionelement of one of the planetary units and output element of the otherplanetary gear unit, the output element of one of the planetary gearunits being directly connected to the output shaft and drivingly engagedwith the input and reaction elements, the reaction element of the otherplanetary gear unit being drivingly engaged with the input and outputelements thereof, a multiple brake mechanism including a two-way brakedevice connected to each of said reaction elements for respectivelyconditioning said planetary gear units for transmission of power at aforward reduction drive ratio and a reverse drive ratio between theinput and output shafts, releasable one-way brake means engageable withat least one of the reaction elements for transmission of relativelyhigh torque at the forward reduction gear ratio when engagedsimultaneously with one of the two-way brake devices and a relativelylower torque when engaged alone, and clutch means mounted by the inputshaft and engageable with one of the elements of said one of theplanetary gear units for direct drive between the input and outputshafts.

2. The transmission defined in claim 1 wherein said drive meanscomprises a hydro-dynamic torque converter having an impeller connectedto the input shaft and a driven turbine, and a drum member enclosing theplanetary gear units and connected to said turbine, said input elementsof said planetary gear units being fixedly mounted on the drum member.

3. The transmission defined in claim 2 wherein said multiple brakemechanism is mounted in axially spaced relation to the drum member, oneof the two-way brake devices and releasable one-way brake means beingmounted on the control shaft projecting axially from the drum member incoaxial relation to the output shaft.

4. The transmission defined in claim 3 wherein said other of theplanetary gear units includes a second reaction element for conditioningthe transmission for reverse drive and an intermediate forward reductiongear ratio, said second reaction element being connected to a separatetwo-way brake device and a releasable one-way brake means simultaneouslyengageable for transmission of high torque at the intermediate reductiongear ratio.

5. The transmission defined in claim 4 wherein the input elements of theplanetary gear units are orbit gears enmeshed with separate sets ofplanet pinions, said sets of planet pinions respectively meshing withsun gears secured to the control shaft and constituting theinterconnected reaction and output elements of the planetary gear units,the output element of said one of the planetary gear units rotatablymounting one set of the planet pinions while the reaction element of theother of said planetary gear units rotatably mounts the other set ofplanet pinions.

6. The transmission defined in claim 5 wherein the other set of planetpinions comprises compound gear elements meshing with the output elementand said second reaction element.

7. The transmission defined in claim 1 wherein said drive meanscomprises a hydro-dynamic torque converter having an impeller connectedto the input shaft and a driven turbine, and a drum member enclosing theplanetary gear units and connected to said turbine, said input elementsof said planetary gear units being fixedly mounted on the drum member.

8. The transmission defined in claim 7 wherein said multiple brakemechanism is mounted in axially spaced relation to the drum member, oneof the two-way brake devices and releasable one-way brake means beingmounted on the control shaft projecting axially from the drum member incoaxial relation to the output shaft.

9. The transmission defined in claim 1 wherein said other of theplanetary gear units includes two reaction elements for respectivelyconditioning the transmission for reverse drive and an intermediateforward reduction gear ratio, one of said two reaction elements beingconnected to a separate two-way brake device and the releasable onewaybrake means simultaneously engageable for transmission of high torque atthe intermediate reduction gear ratio.

10. The transmission defined in claim 1 wherein the input elements ofthe planetary gear units are orbit gears enmeshed with separate sets ofplanet pinions, said sets of planet pinions respectively meshing withsun gears secured to the control shaft and constituting theinterconnected reaction and output elements of the planetary gear units,the output element of said one of the planetary gear units rotatablymounting one set of the planet pinions while the reaction element of theother of said planetary gear units rotatably mounts the other set ofplanet pinions.

11. A variable speed transmission for vehicles compris ing an inputshaft, a hydrodynamic torque converter having an impeller connected tothe input shaft and a driven turbine, at least two planetary gear unitshaving interconnected input elements oontinuously driven by the turbine,said planetary gear units including separate sets of planet pinionsmeshing with said input elements, an output shaft drivingly connected tothe set of planet pinions of one of said gear units, a control shaftcoaxially mounted on said output shaft, interconnected gear elementssecured to said control shaft in meshing relation With said sets ofplanet pinions, selectively braked carrier means rotatably mounting theset of planet pinions of the other of said gear units to condition bothgear units for reverse drive between the input and output shafts,releasable one-way brake means engageable with the control shaft tocondition only one of the planetary gear units for forward drive at areduction gear ratio and direct drive when the hydrodynamic torqueconverter is in a coupling stage, clutch means mounted by the outputshaft for producing direct drive between the input and output shafts andtwoway brake means selectively engageable with the control shaftsimultaneously with the one-way brake means to positively condition saidone of the gear units at the reduction gear ratio when the hydrodynamictorque converter is in a torque multiplying stage.

References Cited by the Examiner UNITED STATES PATENTS 1,256,373 2/18Rowledge 74761 2,518,824 8/50 Simpson 74-763 2,755,688 7/56 Swennes74--688 2,856,794 10/58 Simpson 74-763 2,895,344 7/59 Holdeman et al.

3,000,233 9/61 Roche 74--688 DON A. WAITE, Primary Examiner.

11. A VARIABLE SPEED TRANSMISSION FOR VEHICLES COMPRISING AN INPUTSHAFT, A HYDRODYNAMIC TORQUE CONVERTER HAVING AN IMPELLER CONNECTED TOTHE INPUT SHAFT AND A DRIVEN TURBINE, AT LEAST TWO PLANETARY GEAR UNITSHAVING INTERCONNECTED INPUT ELEMENTS CONTINUOUSLY DRIVEN BY THE TURBINE,SAID PLANETARY GEAR UNITS INCLUDING SEPARATE SETS OF PLANET PINIONSMESHING WITH SAID INPUT ELEMENTS, AN OUTPUT SHAFT DRIVINGLY CONNECTED TOTHE SET OF PLANET PINIONS OF ONE OF SAID GEAR UNITS, A CONTROL SHAFTCOAXIALLY MOUNTED ON SAID OUTPUT SHAFT, INTERCONNECTED GEAR ELEMENSTSSECURED TO SAID CONTROL SHAFT IN MESHING RELATION WITH SAID SETS OFPLANET PINIONS, SELECTIVELY BRAKED CARRIER MEANS ROTATABLY MOUNTING THESET OF PLANETS PINIONS OF THE OTHER OF SAID GEAR UNITS TO CONDITION BOTHGEAR UNITS FOR REVERSE DRIVE BETWEEN THE INPUT AND OUTPUT SHAFTS,RELEASABLE ONE-WAY BRAKE MEANS ENGAGEABLE WITH THE CONTROL SHAFT TOCONDITION ONLY ONE OF THE PLANETARY GEAR UNITS FOR FORWARD DRIVE AT AREDUCTION GEAR RATIO AND DIRECT DRIVE WHEN THE HYDRODYNAMIC TORQUECONVERTER IS IN A COUPLING STAGE, CLUTCH MEANS MOUNTED BY THE OUTPUTSHAFT FOR PRODUCING DIRECT DRIVE BETWEEN THE INPUT AND OUTPUT SHAFTS ANDTWOWAY BRAKE MEANS SELECTIVELY ENGAGEALBE WITH THE CONTROL SHAFTSIMULTANEOUSLY WITH THE ONE-WAY BRAKE MEANS TO POSITIVELY CONDITION SAIDONE OF THE GEAR UNITS AT THE REDUCTION GEAR RATIO WHEN THE HYDRODYNAMICTORQUE CONVERTER IS IN A TORQUE MULTIPLYING STAGE.